Muon spin rotation experiments on a stoichiometric sample of the non-Fermi liquid (NFL) heavy-fermion compound UCu_4Pd, in which recent neutron Bragg scattering measurements are consistent with an ordered structure, indicate that the U-ion susceptibility is strongly inhomogeneous at low temperatures. This suggests that residual disorder dominates NFL behavior. The data also indicate a short correlation length (\lesssim 1 lattice spacing) for this inhomogeneity and a rapid low-temperature U-moment relaxation rate (\gtrsim 10^{12} s^{-1}), which constrain cluster-based models of NFL behavior.
@article{arxiv.cond-mat/9804329,
title = {Susceptibility inhomogeneity and non-Fermi liquid behavior in nominally ordered UCu_4Pd},
author = {D. E. MacLaughlin and R. H. Heffner and G. J. Nieuwenhuys and G. M. Luke and Y. Fudamoto and Y. J. Uemura and R. Chau and M. B. Maple and B. Andraka},
journal= {arXiv preprint arXiv:cond-mat/9804329},
year = {2009}
}